AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 6 599-G603, Copyright © 1983 by American Physiological Society
Adaptation of intestinal muscle in bypassed loops after jejunoileal bypass in rat
P. R. Nemeth, D. J. Kwee and N. W. Weisbrodt
The function and structure of intestinal smooth muscle in the bypassed
intestine of rats with 70% intestinal bypass were compared with the
function and structure of muscle from equivalent areas of intestine from
transected and nontransected controls. Muscle function was assessed by
evaluating changes in intestinal transit. At all times studied after
operation, transit in transected controls was identical to that seen in
nontransected controls. In the bypassed intestine at 3 days after
operation, transit in fasted animals was significantly slower than
intestinal transit in either control group. Over a period of 14-35 days,
transit in the bypassed intestine of fasted animals returned toward control
values. In fed animals, on the other hand, transit was delayed when
measured at both 3 and 35 days after bypass operation. These findings
demonstrate a persistent change in muscle function in bypassed intestine in
response to the ingestion of a meal. No changes in intestinal structure
were found when bypassed intestine was compared with tissue from transected
controls. Thus there were no indications of mucosal or muscular atrophy in
the bypassed intestine. The weights of the combined submucosal, muscular,
and serosal layers in the study segments were increased at 35 days after
either bypass or transection compared with tissue from nontransected
controls. These changes appear to be a nonspecific result of operation.
